Proteomic Analysis of C. elegans Insulin Signaling. Abstract. Diabetes is a common metabolic disease frequently associated with defects in insulin signaling. The model organism C. elegans has emerged as an excellent system to study the insulin signaling pathway, which is highly conserved between humans and C. elegans. This proposal seeks to utilize mass spectrometry-based protein identification and quantification technologies developed in our lab to identify and characterize novel components of the C. elegans insulin signaling pathway. To find out if protein cofactors and post-translational modifications of basic components in this pathway help define a specific signaling outcome, tagged DAF-2 (C. elegans insulin receptor) and DAF-16 (FoxO forkhead transcription factor) will be purified from C. elegans and analyzed by mass spectrometry to identify these cofactors and modifications in relation to signaling conditions. Downstream targets of insulin signaling will be identified using 15N metabolic labeling and quantitative proteomic analyses of wild type, daf- 2 and daf-16 mutants. Novel insulin signaling components identified in this study will be inactivated using RNAi and C. elegans insulin signaling assays will be used to assess their physiological significance. Proteomic analysis of the insulin signaling pathway in conjunction with C. elegans genetics will lead to a better understanding of insulin signaling and provide new therapeutic targets for treatment of diabetes. Public Health Relevance: The body of knowledge produced by this proposal will give insights to the mechanism of insulin signaling and the underlying abnormalities in the diseased state. This can form the basis of future anti-diabetic treatments.